The invention relates generally to seals. In particular, the invention relates to seals used in transitional areas from, for example, a flange to a pipe.
It is known in the art to provide a seal having an elastomeric shaped ring, which is to be pushed onto a cylindrical circumferential surface and supports itself on the latter by a radially acting sealing surface. The shaped ring has an embedded inner ring, consisting of a chamber portion, likewise to be pushed onto said circumferential surface, and having a sealing chamber which surrounds the shaped ring, has an undersize relative to the outer contour of said shaped ring and conically widens from the open inside diameter of the chamber portion towards one face of the chamber portion. The seal also comprises fastening means which fix the chamber portion with respect to a second component resting against the aforesaid face of the chamber portion.
Such a seal is disclosed by German Utility Model No. 8,436,214. This reference discloses a pipe connection between two pipe ends to be connected abutting one against the other, onto each of which a flange, a clamping element and a chamber portion are loosely pushed and can be braced with respect to one another by a screwed union. A seal in the form of an elastomer shaped ring with an embedded inner ring surrounds the connecting joint and protrudes by its two axial ends into a sealing chamber of the two chamber portions. The flange and chamber portions form between themselves in each case a clamping chamber, into which enters the said clamping element, which supports itself against the pipe end by a radially inner-lying clamping rim, and has, with regard to a radially outer-lying clamping rim, a clamping surface of the clamping chamber engaging over it and protrudes in an axial direction out of the clamping chamber in such a way that an axial compressive force acting on the clamping element results in a decrease in the outside diameter and in a decrease in the inside diameter of the clamping element. The outer circumferential surface of the elastomer shaped ring is designed approximately semicircular, the two outer ring rims of the shaped ring which support themselves against the circumferential surface of the two pipe ends being provided with a radius. This radius is greater than the sum of the plus and minus tolerances of the pipe diameters plus the fitting clearance between the inside diameter of the chamber portions and the largest tolerance of the pipe diameters. Embedded in the elastomer shaped ring is an inner ring of hard and/or plastic material. The outer contour of the shaped ring corresponds approximately to that of the two sealing chambers in the chamber portions, but is oversized, so that a pressing together of the two chamber portions distorts the seal and subjects it to a pressure which is directed axially and radially inward. The inner ring supports itself--just like the elastomer shaped ring--against the circumferential surfaces of the two pipe ends.
With this previously known seal, complete pipe connections or other components are sealed off in an advantageous way provided that pipes or pipe-like components are used for the support of the two radially acting sealing surfaces lying on either side of the inner ring. However, this previously known system is not suitable for the transition from flanges based on flat seals to a pipe connection according to the design described above. This is so in this case because outside the pipe wall there are sealing surfaces which are perpendicular to the pipe axis.